DESCRIPTION (Taken directly from the application) This is a competitive renewal of the New York Obesity Research Center (NYORC). The NYORC integrates the obesity research programs situated at the St. Luke's-Roosevelt Center and New York Presbyterian Hospital Center of Columbia University, Cornell Medical College, and the University of Vermont. The objectives of the combined center include the following: (i) to bring together, under the Center's aegis, a critical mass of independent investigators of separately funded research projects who share a strong interest in the study of obesity-related problems; (ii) to manage the pilot and feasibility (P/F) program and the program enrichment activities to promote and test new research ideas, stimulate productivity, foster the development of talented new investigators in the field, and persuade creative scientists working in areas or disciplines not ordinarily concerned with obesity to become involved in obesity-related research; (iii) to provide participating investigators of funded projects relevant to obesity research with valuable laboratory, technical and educational services that otherwise would not be available, thereby improving the productivity and efficiency of their operations; and (iv) to maintain a dynamic focus for obesity-related investigation, so as to move the field more effectively into basic and applied research critical to the solution of key problems. Seven Cores offer a comprehensive spectrum of services: funding is requested for 6 of them in this application; (i) the Administrative Core, which provides a structure for peer evaluation of P/F protocols, training initiatives, a Sub-Core for Biostatistical/Computational services and an enrichment program; (ii) a Body Composition/Energy Expenditure Core (iii) a Hormone/Metabolite and Mass Spectrometry Core; (iv) a Molecular Biology/Molecular Genetics Core: and (v) an Ingestive Behavior Core. No funding is requested for the other two cores, (vi) an In-Patient General Clinical Research Center Core for conduct of rigorously controlled metabolic studies, located at both St. Luke's-Roosevelt and New York Presbyterian, and (vii) an Out-patient Core for clinical investigation of obesity at St. Luke's-Roosevelt.